<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>

    </style>
</head>

<body>

</body>
<script>
    const p = new Promise((resolve, reject) => {



        //1.创建对象
        const xhr = new XMLHttpRequest();

        //2初始化
        xhr.open("GET", "https://api.apiopen.top/getJoke")
        //3发送
        xhr.send();
        //4绑定事件
        xhr.onreadystatechange = function () {
            if (xhr.readyState === 4) {
                //响应状态码
                if (xhr.status >= 200 && xhr.status < 300) {
                    //表示成功

                    resolve(xhr.response)
                } else {
                    //如果失败
        
                    reject(xhr.status)
                }
            }
        }
    })
    //指定回调

    p.then(function(value){
        console.log(value);
    },function(reason){
        console.error(reason)
    })
</script>

</html>